Concept explainers
Density-dependent factors regulate population growth (pp. 1200-1205)
• ln. density-dependent population regulation, death rates rise a net birth rates fall with increasing density. A birth or death rate that does not vary with density is said to be density independent.
• Density-dependent changes in birth and death rates curb population increase through negative feedback and can eventually stabilize a population near its
• Because changing environmental conditions periodically disrupt them, all populations exhibit some size fluctuations. Many populations undergo regular boom-and-bust cycles that are influenced by complex interactions between biotic and abiotic factors. A metapopulation is a group of populations linked by immigration and emigration.
Give an example of one biotic and one abiotic factor that contribute
to yearly fluctuations in the size of the human population.
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CAMPBELL BIOLOGY W/ACCESSCODE
- Answer each question in a clear and organized manner (maximum of 10 sentences). 1. Describe population growth and population regulation. Give an example of how density-dependent and density-independent factors might interact. 2. Discuss the levels of organization of living systems.arrow_forwardHuman populations have which type of survivorship curve? a. Type I b. Type II c. Type III d. Type IVarrow_forwardThe maximum rate at which a population could increase under ideal conditions is known as its (a) total fertility rate (b) survivorship (c) intrinsic rate of increase (d) doubling time (e) age structurearrow_forward
- In a graph of population size versus time, a J-shaped curve is characteristic of (a) exponential population growth (b) logistic population growth (c) zero population growth (d) replacement-level fertility (e) population growth momentumarrow_forwardMatch each term with its most suitable description. _____ carrying capacity a. maximum rate or increase per individual under ideal conditions _____ exponential growth b. population growth plots out as an S-shaped curve _____ biotic potential c. maximum number or individuals sustainable by the resources in a given environment _____ limiting factor d. population growth plots out as a J-shaped curve _____ logistic growth e. essential resource that restricts population growth when scarcearrow_forwardWhich factor is not responsible for the large increase in the human population over the last 300 or so years?a. Larger and more reliable food reserves from the modernization of farming techniquesb. Decreasing mortality rate due to improvements in medicinec. Increasing amounts of open space as countries developd. Increased sanitation practicesarrow_forward
- Which of the following forces can de-stabilize a population, resulting in a unstable equilibrium? a. short time lags in birth rates or death rates b. inverse density dependence c. density-dependent natality d. moderate competition e. density-dependent mortalityarrow_forwardThe carrying capacity refers to the Group of answer choices: maximum sustainable population size for the prevailing environment. maximum growth rate of a population in which resources are unlimited. minimum amount of resources needed to sustain a finite population with zero population growth. minimum number of individuals in a population required to assure reproductive success.arrow_forwardUnder logistic population growth what happens as N becomes similar in size to K? Group of answer choices a. population growth speeds up b. K shrinks c. K expands d. population growth approaches zero e. population growth becomes negativearrow_forward
- A population may pass through changes in age structure without changing in size. Do you agree or disagree? Justify.arrow_forwardCalcuate the lx(Survivorship which is equal to proportion of population surviving from birth) and survivorship per 1000 individuals S1000= lx*1000. Calculate Fecundity bxarrow_forwardA population of white-footed mice becomes severely overpopulated. Which of the following represents a density-independent control on population growth of these mice? Decreased immune function in the mice due to stress related to overcrowding Increased numbers of owl predators due to the increased number of mice Temperatures much warmer than normal due to increased greenhouse gases, which disrupts the normal breeding cues for these mice Rapid transmission of diseases and parasites amongst the mice Lack of sufficient food and shelter for the high numbers of micearrow_forward
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